The Big Book of Eagles

But let’s start… small: the Pygmy Eagle weights about the same as a pigeon. Whaa-ut? Hieraaetus weiskei is found on New Guinea and some of the surrounding islands. Evolutionary pressures on islands can sometimes result in rather small animals. Interestingly, this species is said to be one of the closest living relatives of the largest eagle ever, the extinct Haast’s Eagle of New Zealand (Harpagornis moorei). The Haast’s was a “33-pound (15kg) giant that preyed on moas” and that died out circa 1400 when the Maori killed off the last of the moas. (Islands can also cause gigantism.) The Pygmy Eagle used to be lumped with Australia’s Little Eagle (Hieraaetus morphnoides), but DNA and other evidence suggests it is its own species. Notwithstanding these small examples, eagles are some of the largest and rarest of birds. The largest recorded wingspan of an existing eagle species belongs to a female Wedge-tailed Eagle: 9’4″. The heaviest, a 20-pound Harpy Eagle. Harpy Eagles are tropical forest birds, so like Accipiters they have relatively short and stocky wings for maneuverability amid trees; while massive birds, they only rank about 6th in terms of wingspan. There is much more such information in this illustrated natural history by Mike Unwin and David Tipling. They cover most of the eagle species found in the world.

Sure, this is a coffee-table book, so the pictures are impressive. But thankfully it’s also one informed by taxonomy, ecology, evolution, and conservation, all the good things. Pictured is an adult Bald Eagle, one of two species of eagle found in the US. This one passed high overhead of me last Saturday in Green-Wood Cemetery here in Brooklyn, approximately the third time I’ve seen one there. Interestingly, it looks like a photographer who was also in Green-Wood that day pictured a lower flying younger bird, easily distinguished because it takes four to five years for the Balds to get their white heads and tails.